LA CROSSE, Wisconsin (AP) -- A man told police he kept his mother's corpse in a basement freezer for more than four years while he collected her Social Security checks, authorities said Monday. A body was found encased in ice, in a sitting position.

Philip Schuth, 52, told police his elderly mother, Edith, died of natural causes in August 2000, but that he didn't tell anyone because he was afraid police would blame him, according to documents filed in court Monday.

He said his mother years beforehand was attacked by a cat and her blood was on the walls in the house they shared, and he feared police would think he killed her, according to the documents.

Police recovered a chest-type freezer in Schuth's basement, and after chipping away at a block of ice, discovered a human knee.

Sheriff's Capt. Jeff Wolf said a body appears to be in the block, intact in a sitting position. The body has not been identified; an autopsy is set for later this week.

Investigators found the freezer at the end of an all-night standoff at Schuth's home in the Town of Campbell, located on French Island in the Mississippi River about 110 miles northwest of Madison. The standoff began Friday when a 10-year-old boy told his father that Schuth had hit him.

The boy's father, mother and the child confronted Schuth at his home. After admitting he had hit the boy, Schuth pulled out a handgun and opened fire, according to court documents. The father was hit three times, and the family fled and called police. The father was treated and released for his wounds.

Schuth retreated into his house and when SWAT teams arrived, he told negotiators he had "more than 10 but less than 100" bombs and 16 firearms, and that it would be "high noon" when he surrendered, according to court documents.

He surrendered early Saturday without incident. Investigators found 15 to 20 homemade explosive devices, packed with nails, heavy staples and other metal items, a sawed-off shotgun along with 15 other firearms, documents said.

La Crosse County District Attorney Scott Horne said he plans to charge Schuth next week with attempted homicide and reckless endangerment for allegedly shooting at the family, as well as having improvised explosives and concealing a corpse.